How to knead concrete or approach the matter with the mind

Mixing concrete - start with the theory

Concrete consists of three components, which should be specially prepared and mixed, the Gulf is all a decent amount of water.You will need to sand, cement and gravel.When using sand important that it was clean, washed, especially not desirable to the presence of even small pieces of clay, because over time it simply destroy your wall.Firstly, the heterogeneity of concrete reduces its strength and consequently, durability, and secondly, at each frost chipping pieces of clay will concrete around.Therefore, concrete kneading should be provided with quality components.

should also carefully select and cement, and gravel. Cement - very moody stuff, demanding to transportation and storage conditions.Therefore, you should buy it from reliable suppliers, the best in specialized stores.Because questionable warehouses where cement could dampen, solidify compacted in lumps, rarely guarantee you quality. Crushed need a clean, no rubbish, and the material from which it is made, is able to strengthen or weaken some characteristics of concrete.For example, expensive granite gravel or rubble will make the solution more durable and resistant to frost and limestone - on the contrary, reduce the quality of concrete.

At the end of the theoretical instructions given should understand the main rule is to mix the concrete: in any case we can not allow lumps, they pose a threat to the integrity of your design, which will be strengthened by this solution.Therefore it is better to use mechanized methods of agitation, because you never hands knead well not even a cubic solution.

How to mix concrete - Ready-mix concrete

Kneading can be done quickly: cement and sand mix thoroughly, then to add rubble, again stir well, then pour the water and bring to a final homogeneity.However, the quality of such a solution is not very high, this process approach more closely.First sand and gravel divided into fractions, the ratio of the quality of which will depend on the concrete and its suitability for certain jobs.

How to knead concrete best quality now will understand steps.First, disconnect the rubble on fractions.This will require several types of mesh.The first gravel fraction should contain a particle size of 11-20 mm, it is taken for a screen with a 10x10 mm cell and screened all rubble that remains in the sieve - the first fraction.The second fraction remains in a sieve of 5x5 mm and a size of 6-10 mm.The third fraction - is what remains in a sieve of 3x3 mm and, respectively, has a size of 4-5 mm.

The same is done with sand, it also breaks up into fractions.Needed with 2.5 mm sieve unit, 1.2 mm, 0.3 mm.The first sieve is taken for clearing sand from impurities, but after sifting through the second we get the first fraction.The second fraction remains in the last sieve.

now look at how to properly mix the concrete, using all the factions.The sand is taken in the following proportions: 20-50% - the first fraction, 50-80% of the second fraction, ie,first fraction should be less.For there are two gravel composition, or only the first (30-35%) and the second (65-70%), of three or 1 - 60% 2 - 30-35%, 3 - 10-15%.This approach to the preparation of the solution will make a very dense and durable concrete, cement and it will need less than usual.Water is 1 cubic solution will require about 170 liters.

How to mix concrete or a few remarks

All these proportions are measured volume fractions , rather than by weight.Kneading should be only the amount of concrete, which will be enough for an hour, after which time he will be unsuitable.Choosing the cement, keep in mind that classes kneaded concrete and cement must differ by 2 units, in the class of cement should be higher.

understand further how to properly mix the concrete.If you want to get some kind of a certain amount, then remember that when mixing the solution was reduced in volume somewhere in the 30-40%, so the calculations take this into account.Number

cement can affect concrete quality, if it is too small.Many special quality of cement will not increase, but the lack of it will lead to low-density, friability and water permeability of the solution, which is undesirable for concrete structures.

Last nuance for the production of concrete - its plasticity .If your solution is too thick, it will be difficult to seal, so it must be fluid, that it fills the entire volume of itself and had to condense (ramming) slightly.But the more the grout less durable, as its density is less.Therefore it is necessary to maintain a middle ground, as well as focus on the method of its use.